Coating roller

ABSTRACT

Apparatus for treating web material which comprises at least one power-transmitting or supporting roller for web material which consists of a rigid roller, the driving surface of which is covered with a helically wound filament. The filament may be of suitable plastics materials, e.g. nylon, or of metal, preferably of stainless steel. The interstices between the roller and the filament may be filled with a resin, preferably by coating the roller with a soft resin before or whilst the filament is applied thereto or alternatively by coating the roller after being wound with the filament with an organic solvent solution of a resin which is able to permeate between the filaments so that when the solvent has evaporated, the interstices are left filled with resin.

United States Patent [191 Jones COATING ROLLER [75] Inventor: DavidPeter Marshall Jones, Ilford,

England [73] Assignee: llford Limited, Essex, England [22] Filed: Sept.20, 1973 [21] App]. No.: 399,137

[30] Foreign Application Priority Data Apr. 15, 1975 Attorney, Agent, orFirmWenderoth, Lind & Ponack [57] ABSTRACT Apparatus for treating webmaterial which comprises at least one power-transmitting or supportingroller for web material which consists of a rigid roller, the drivingsurface of which is covered with a helically wound filament. Thefilament may be of suitable plastics materials, e.g. nylon, or of metal,preferably of stainless steel. The interstices between the roller andthe filament may be filled with a resin, preferably by coating theroller with a soft resin before or whilst the filament is appliedthereto or alternatively by coating the roller after being wound withthe filament with an organic solvent solution of a resin which is ableto permeate between the filaments so that when the solvent hasevaporated, the interstices are left filled with resin.

1 Claim, 2 Drawing Figures COATING ROLLER BACKGROUND OF THE INVENTIONThis invention relates to power-transmitting rollers for traversing webmaterial through treating apparatus.

In most apparatus wherein web material is coated, dried or otherwisetreated, there is at least one powertransmitting roller around which theweb is partially lapped in order to drive or retard the web passingthrough the apparatus. However one of the troubles experienced with suchpower-transmitting rollers is the fault known as aeroplaning that is tosay the web does not tightly lap the roller and thus is not drivenefficiently by the roller. Such aeroplaning is due to air becomingentrapped between the web and the powertransmitting roller. This faultis often overcome by providing a microgroove surface on thepowertransmitting roller. Such a microgroove surface consists typicallyof a groove of the dimensions 0.005 inch deep by 0.055 inch widemachined in a spiral over the entire face of the roller.

Such a microgroove surface improves the grip between the roller and theweb and thus tends to prevent aeroplaning of the web. It also allows asuction to be applied continuously round the roller in order to increasethe grip between the roller and the web when small angles of lap of theweb over the roller have to be employed. However it is both costly anddifficult to obtain a suitable microgroove surface and when the materialof the driving roller has to be chosen for reasons other than ease ofmanufacture these difficulties are increased.

SUMMARY OF THE INVENTION It is the object of the present invention toprovide an apparatus which comprises a power-transmitting roller for webmaterial which has a microgroove surface which is comparatively easy andcheap to prepare.

According to the present invention there is provided an apparatus fortreating web material which comprises at least one power-transmittingroller for web material which consists of a rigid roller, the drivingsurface of which is covered with a helically wound filament. Thefilament may be of suitable plastics materials, e.g. nylon, or of metal,preferably of stainless steel. Most preferably the diameter of thefilament is from 0.0025 to 0.025 inch (i.e. from 0.00635 cm to 0.0635cm).

The surface of the roller of use in the present invention is comparablewith the surface of a roller which has been microgrooved. However, it isvery easy to prepare a helically wound filament covered roller of thistype and moreover if the surface of the roller is damaged in any way thefilament can be removed and replaced by fresh filament. Further if it isrequired that the surface of the roller be stainless steel it ispossible to wind stainless steel wire on to a rigid roller composed ofanother material.

The presence of the filament winding on the roller core enables asuction or negative pressure to be exerted around the roller. This helpsa power-transmitting roller to grip the travelling web.

If it is essential that foreign matter picked up by the driving rollershall not become lodged in the interstices between the roller and thefilament it is preferred that these interstices be filled with a resin.This may be achieved by coating the roller with a soft resin before thefilament is applied thereto or whilst the filament being applied.Alternatively the roller after being wound with the filament may becoated with an organic solvent solution of a resin which is able topermeate between the filaments so that when the solvent has evaporated,the interstices are left filled with resin.

The power-transmitting filament-covered driving roller of use in thepresent invention may be used not only to drive a web through anapparatus but also simultaneously to support a web at the point ofapplication of a liquid coating on the web. This use is shown in theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings will serveto illustrate the invention.

FIG. 1 is a diagrammatic cross-sectional view of a travellingweb-treating apparatus which comprises a wire wound driving roller ashereinbefore described.

FIG. 2 is a side elevation of the wire wound driving roller used in FIG.1.

DETAILED DESCRIPTION OF THE DRAWINGS In FIG. 1 a film web 1 is beingunwound from a stock roll 2 by a driving roller which is also acting asa coating roller. The driving roller 4 is a mild steel roller the entiresurface of which has been covered with a helically wound stainless steelwire of 0.0075 inch diameter. The wire has been wound on to the mildsteel core after the core has been covered with a layer of resin. Thisensures that the interstices between the wire strands are filled withthe resin so that any particles picked up from the web can not becomelodged there. The helically wound wire on roller 4 is shown in FIG. 2.

The web 1 passes over various free-running rollers 3, both before andafter roller 4. The web 1 is partially lapped around roller 4 which ispartially immersed in aqueous coating liquid 6 in a treating materialreservoir such as trough coating applicator 5. Thus the roller 4 servesto pull the web 1 off the stock roll 2 and to support the web at thepoint of application of the aqueous coating liquid 6 on to the web.After the web has been coated with the liquid 6 it is led into a dryingcabinet 7 and then is wound on to another stock roll 8 which isrotatably driven.

The grip exerted on the web by the wire covered roller 4 is increased bythe suction created by two suction tubes 9. This creates continuously anegative pressure around the roller.

The angle of lap of the web 1 over the driving roller 3 is shown to berather small. This often occurs when it is required to fit a webprocessing apparatus into an already built and confined space. Thepresence of the wire winding on the core of the roller ensures that thedriving roller is able to exert a good grip on the web. The strength ofthis grip in increased by the suction effort created by the suctiontubes 9. The presence of the wire winding on the roller does not effectthe uniformity of the coating on the web and no marks due to thewirewinding are present on the final dried coating.

I claim:

1. An apparatus for treating web material, said apparatus comprising atleast one power-transmitting roller for driving said web material andcomprising a rigid roller, the outer surface of which is covered with ahelically wound stainless steel wire having a diameter of from 0.00635to 0.0635 cm. and a resin filling the interstices between said stainlesssteel wire and said roller.

1. AN APPARATUS FOR TREATING WEB MATERIAL, SAID APPARATUS COMPRISING ATLEAST ONE POWER-TRANSMITTING ROLLER FOR DRIVING SAID WEB MATERIAL ANDCOMPRISING A RIGID ROLLER, THE OUTER SURFACE OF WHICH IS COVERED WITH AHELICALLY WOUND STAINLESS STEEL WIRE HAVING A DIAMETER OF FROM 0.00635TO 0.0635 CM. AND A RESIN FILLING THE INTERSTICES BETWEEN SAID STAINLESSSTEEL WIRE AND SAID ROLLER.